Timing device for fuel injection pumps



Aprii 3941 J. H. BERTRAM ZQEQfiW TIMING DEVICE FOR FUEL INJECTION PUMPS Filed Oct. 14 1938 2 Sheets-Sheet l A itorneys 9 31%? J. H, BERTRAM 223%,,587

TIMING DEVICE FOR FUEL INJECTION PUMPS Filed Oct. 14 1958 2 Sheets-Sheet 2 my, (Z Inventor dfi'flfira ranz n A itomeys Patented Apr. 22, 1941 UNITED STATES PATENT OFFICE TIMING DEVICE FOR FUEL INJECTION PUMPS I 1 Claim.

This invention is a device for use in accurately timing the injection point of fuel pumps used on various types of Diesel motors; and the invention together with its objects and advantages will be understood from a study of the following description taken in connection with the accompanying drawings wherein-- Figure l is an elevational view of the device.

Figure 2 is a sectional view therethrough with certain parts omitted.

Figure 3 is a horizontal sectional view taken substantially on the line 3-3 of Figure 2.

Figure 4 is a perspective view of a plunger member.

Figure 5 is a horizontal sectional view taken substantially on the line 5-5 of Figure 1, and

Figure 6 is a top plan view of the device.

Referring more in detail to the drawings it will be seen that in the preferred embodiment thereof the device comprises a body member 5 H in the form of a suitable casting provided at about the center thereof with a chamber 6 to which leads a passage 1 that extends inwardly from a threaded pin or nipple 8 through the medium of which the device is tapped into or attached to the injection pump under test.

Leading from the chamber 6 is a passage 9 that joins with a passage ID that extends at right angles to the passage 9 and opens to the atmosphere.

For controlling the flow through the passages 9 and Hi there is provided at the junction of said passages a needle valve H which threads into a bore provided therefor in the body 5, and for the needle valve H there is provided at the end of the passage 9 remote from the chamber 6 a seat I2.

The body 5 is also provided with a bore l3 that extends to the chamber 6 and accommodates a plunger l4 that at its inner end is equipped with a suitable packing cup [5.

Supported above the top of the body member 5 is a plate Hi, the member l6 being supported through the medium of a pair of short posts or studs 11.

The studs ll have reduced upper ends that extend through openings provided therefor in the plate It and on said reduced upper ends are collars 18 of insulating material. At said reduced upper ends the studs or posts 11 are also threaded to receive nuts 19 while at the lower ends thereof the studs or posts I! have threaded pins 20 which thread into the top of the body member 5.

Carried by the bar It is a micrometer assembly which includes a tubular body member 20 that is tapped into the cross bar IS. The body member 20 is of course internally threaded to complement the threads of a micrometer screw 2| that is in direct alignment with the plunger M.

The gauge or scale-carrying member 22 of the micrometer is of course carried by the upper end of the screw 2| and has a telescoping fit with the body 20.

The posts or studs l! are of conductive material and extending inwardly from one of the posts or studs I! is a spring contact finger 23 that has a free end engaging a collar 24 carried by the plunger M which, together with the body member 5, is also of conductive material.

Further in accordance with the present invention there is provided a battery circuit which embodies a battery B, a manually operable switch S, an audible electrically operable signal device A, which latter is in the form of a bell, and a visual electrically operable signal device L, which in the present instance'is in the form of an electric bulb. The signalling devices A, L, and the switch S may be arranged wherever found convenient.

A conductor 26 leads from one terminal of the battery to one 01' the posts I! and a conductor 21 leads from the battery and has the switch S therein and also leads to the signal device A and the lamp L and is connected to the terminal 28 on the member l6, these parts being so arranged that when the upper end of the plunger I4 is in engagement with the screw 2! the circuit will be completed to the bell and lamp so that the bell will ring and the lamp will be lighted. However, when the plunger 14 is separated from the screw 2i the circuit will be broken. The spring 23 engaging the collar 24 of the plunger M will act to hold the plunger in lowered position and this arrangement also insures a good electrical connection between the parts when the plunger is in contact with the screw 2| for if only the plunger was relied upon to carry the current to the screw 21 the film of oil between the plunger and the walls of the bore l3 in body 5 might interfere with the passage of current but with the use of the spring the current will flow from the screw 2|, plunger I4, collar 24 and spring 23 through the parts of the device to the conductor 26.

In actual practice the body member 5 is,

through the medium of the nipple 8, tapped into,

or otherwise connected with the fuel pump. After thisconnection is made valve II is moved to an open or unseated position and the pump being tested will pump oil through the passage 1 into the chamber 6 until a steady fiow of fuel passes from the chamber 6 through the passages 9 and I0, when the valve I I is moved to a seated or closed position. This will remove any air in the passage 1 and chamber 6 and prime the device and then the device is ready to test the pump.

To make the test the Diesel motor is turned over until the pump being tested starts up on the injection stroke. The operator continues to turn the motor slowly until the fluid in the chamber 6 forces the plunger l4 upwardly into contact with the adjusting screw 2| of the micrometer whereupon the circuit through the signal devices is completed, which point of contact is now the actual injection point of the pump.

The operator now backs ofi the micrometer screw 2| to break contact thereof with the plunger I4. Next the operator determines by the timing mark on the motor whether injection is late or not. If the injection is found to be late the operator then backs up or reverses the motor until the pump piston returns to the bottom of its stroke when the motor is then turned forwardly to the timing mark. When this has been done the operator adjusts the pump so that the signal devices will again operate thus indicating that the pump is now properly set.

It should be understood that the different weights of fuel used in the fuel injection systems on Diesel motors cause a slight change in the injection timing. All motors are timed to have injection start a certain number of degrees ahead of crank top or piston top dead center. The fuel pump port closing corresponds with this timing.

If wear occurs in the mechanism that drives the pump, or the cut-off portion of the pump plunger itself is worn enough to let part of the fuel by-pass through the worn part, then injection is delayed. Therefore, with my timing device the fuel pump, can be set to the actual closing or cut-off of the pump and it is at this point from where the time is set regardless of the weight of fuel used in the system. The factory markings on the machine are for the fuels they recommend and an allowance is made for variations in the setting, for line lag and length of lines, and injection pressure are all allowed for in the original setting. Therefore, with my device, the actual cut-off or by-pass port closing is indicated by the closing of the alarm circuit.

It should be understood that the pump being timed, checked, or reset, has a built-in check valve to prevent the fuel from returning to the pump chamber. After fuel is forced into the line, therefore, with my timer attached to the pump, every particle of fuel that once enters the timer is held in the chamber 6. Adding fuel to the chamber 6 raises plunger l4 and makes contact with screw 2|, which is set to a very closecontact gap, say /2 thousandth of an inch.

When this setting has once been made, the motor is turned over slowly until the pump comes up on the injection stroke and the instant the port closes on the pump, fuel is forced into the chamber 6 and raises the plunger I4, making contact with screw 2|, thus closing the electrical circuit and indicating the injection point of the pump or port closing.

In order to get another check on the pump being timed it is necessary to return the plunger in the pump to where another charge of fuel can enter the pump chamber, and to do this the motor must be either turned backwards far enough to return the plunger, or, on a two-cycle motor, one full revolution forwards. On a fourcycle, two complete revolutions. However by rocking the motor back and forth, the motor need not be turned back and forth more than 50 degrees to obtain the same effect that would be secured by turning the motor over to the next injection stroke of the pump.

The use of the micrometer screw is to reset the device for every check that is taken. For instance, after once checking the pump, and the timing marks noted, if it is wished to make another check on the pump, back the motor up, 50 degrees, and the fuel in the chamber 6 remains the same and the electrical circuit is still closed. Back off the screw 2i until the signal ceases. Then, turn the motor forward again until the signal again comes on and the signal again will come on in identically the same spot on the crank throw. Then, if not correct, the proper adjustments are made on the pump lift or mechanism that drives same, to make the timing mark on the motor to correspond with the electrical signal. When the signal comes on at the time the timing marks are in line, the pump is properly set.

The micrometer screw is merely a reset for the electrical system, as every particle of fuel forced into the chamber 6 remains there and the signal is on until screw 2| is released or the pressure is released through bleeder screw ll. Then the contact spring 23, will return the plunger I4 to the bottom of the stroke. Screw 2| should be turned the same distance as noted by the gage part thereof, each time the screw is backed off.

It is thought that a clear understanding of the construction, utility and advantages of an invention of this character will be had without a more detailed description thereof.

Having thus described the invention what is claimed as new is:

In a device of the class described, a body having a vertically arranged chamber therein passing through its top and a fluid inlet passage extending from the bottom of the chamber through the lower end of the body, said body also having a passage extending horizontally from the lower end of the chamber through a side portion of the body and said passage having a valve seat intermediate its ends, said body also having a vertically arranged passage therein extending from its upper surface downwardly to the horizontal passage where it connects with the horizontal passage between the valve seat forming part and the outer end of the horizontal passage, a valve passing through the outer part of the horizontal passage for engaging the seat to prevent flow of fluid through the vertical passage when the valve is closed, a pair of uprights having their lower ends connected with the top of the body, a plate having its ends supported by the upper ends of the uprights, means for insulating the said ends of the plate from the uprights, a plunger in the chamber with its upper portion passing from the top of the chamber, an enlargement on said upper portion, a spring carried by one of the uprights and engaging the enlargement for holding the plunger in lowered position, a micrometer assembly carried by the plate and including a screw depending from the plate in alignment with the plunger and engaged by the plunger whenthe plunger is forced upwardly by fluid entering the chamber, a terminal member connected with the plate and adapted to be connected with an electric circuit which is adapted to be connected with one of the uprights.

JOHN H. BERTRAM. 

